Went to the Dyno today.. Weird Issue?

[fe9_fe9]

Hey all,

Car is 2005 C6 with a 402 with an HP Performance Twin Turbo Kit and Methanol. Turbos are T3\T4 57 mm.

We managed to pull 746 RWHP and 911 RWTQ. I got a boost spike during this run since I increased the gate pressure a bit. Boost reached 21 psi then went back to a steady 18 psi. After this run, the car didn't go back to normal. The car is idling at around 1150 after it was normally at around 850. Didn't go back to the normal temp. It was around 8 degrees warmer. Every run I have done afterwards I was getting an average of 4 KR. Even when I took the boost down to 11 psi. Timing was at around 11* and AFR was between high 10's and low 11's. No C16 yet. So we called it off and took the car back home.

Any idea what could cause this? I appreciate the help.

[Xjas]

Sounds like you've blown out an intake manifold gasket or split the intake manifold.

[fe9_fe9]

Found it

I capped the barb off the intake manifold on the passenger side. After that run, the cap took off

Will put another one on with a clamp to hold it in place

[10_SS]

Sounds like you've blown out an intake manifold gasket or split the intake manifold.

then this is the winner! Vacuum leak!

[fe9_fe9]

then this is the winner! Vacuum leak!

Yes indeed

[fe9_fe9]

Sounds like you've blown out an intake manifold gasket or split the intake manifold.

Thank you very much for your great hint. It really helped me identify the main cause of the problem when I went and checked the manifold